The first tragedy of 2009, and an especially sad one: TMZ reports that Jett Travolta, 16, died today while on vacation with his father John and mother Kelly Preston.

Neither the cause of death nor any other details are available, though we imagine Anonymous and other Scientology critics will drop in with their own suspicions by the time you finish reading this sentence. Jett was long rumored to be autistic, a condition that went untreated while his parents instead claimed he suffered from Kawasaki syndrome — a children's illness characterized by fever, rash, swollen lymph nodes, and potentially leading to heart disease. Developing...

UPDATE (1:21 p.m.): Reuters reports that Jett suffered a seizure at the family's vacation home. Travolta attorney Michael Ossi confirmed the details, adding that attempts were made to revive him, but he died at the scene.